For the manufacturing of fibre concrete, or concrete reinforced with reinforcing fibres, it is extremely important to supply or dose the exact quantity of reinforcing fibres to the mixture of components of mortar or concrete. Once integrated in the concrete, the fibres also need to have a homogeneous distribution to assure a correct reinforcement and quality.
Numerous solutions have already been proposed, such as in EP-A-522.029 (WO 91/14551); EP-A-499.572; EP-A-499.573; DE 29714704U; DE-A-3.412.216; DE-A-4.427.156; FR-A-2.672.045, U.S. Pat. No. 4,284,667 and U.S. Pat. No. 6,945,686 and many other patent documents.
Despite the existence of a lot of solutions to supply the exact amount and type of fibres into concrete and to improve homogeneity of distribution of fibres into concrete, there is still a need to further improve dosing and distribution of fibres in concrete.
Another disadvantage of the existing situation is that once the fibres are in the concrete, fresh or hardened, it is difficult to control the quality of the fibre reinforced concrete, i.e. not only the right type and quantity of fibres that have been used, but particularly the actual fibre distribution within the concrete. Wash-out tests are carried out on site to ensure that the correct amount of reinforcing fibres has been dosed into the concrete and distributed homogeneously. This is time consuming, requires special equipment and might deliver results too late.
Non-destructive magnetic field testing apparatus exists, but this requires pouring concrete in a mould. For a hardened concrete structure, this still involves drilling a core out of the structure. These tests are however limited to steel fibres and there is no continuous measurement possible. Non-steel fibres, such as e.g. polypropylene fibres, are being used more and more extensively as reinforcement for concrete and other structures. There exists an urgent need for control mechanisms to check the correct type, amount and distribution of steel and non-steel reinforced concrete, even when the concrete structure has been there for years.
JP2005-330729 discloses the use of a radio IC tag to provide information about a concrete member so that said information is not lost or does not hinder the appearance and the workability of the concrete member. Since the tag may deteriorate over years and may produce a malfunction, two or more tags are applied underground in a concrete member. The tags may also be fixed to a steel rod placed in the concrete. However, said tags are used solely for the purpose of providing information about the concrete member as such. The information is pre-stored on the tag, meaning that the proportioning and/or mixture ratio is stored as information on the tag, but does not provide any guarantee or examining about the actual proportioning or mixing ratio in the concrete.
It is a particular purpose of the present invention to provide information about a fibre reinforced concrete post-mixing and/or post-hardening.
The invention intends to avoid aforementioned disadvantages.
It is an object of the invention to provide intelligence to fibre reinforced concrete and fiber reinforced concrete structures.
It is also an object of the invention to provide a simple method for dosing fibres in concrete.
It is another object of the invention to provide a method for determining the content and quality of concrete reinforcement, such as the amount of fibres, origin, distribution, concentration and/or type of fibres.